Stressful family transitions can take a toll on all family members and on relationships within families. Military deployment has been associated with compromised mental health in non-deployed spouses and young children of service members; yet, adolescents have been underrepresented in studies of risk in military families. The proposed study addresses limitations in current scientific knowledge by elaborating the intersection of multiple domains of risk among adolescents experiencing parental military deployment. These risks include: developmental changes in adolescence, youth psychosocial responses to deployment, and stress in the immediate family context (i.e, the youth's relationship with the non-deployed parent]. Internalizing disorders (i.e., depression, anxiety) and risk taking behaviors (i.e., substance use, risky sexual behavior), which often emerge in adolescence, are examined as potential problems associated with the parent's military deployment. Youth may be especially vulnerable to developing these symptoms due to the inaccessibility of the deployed parent, and the spillover of stress from the other parent. The proposed study directly assesses conversations between the non-deployed parent and adolescent to examine how the civilian parent and adolescent talk about deployment and about other family issues. Interaction behaviors, linguistic cues, and emotional arousal are measured as explanatory mechanisms linking deployment and adolescents' mental and behavioral health. The transmission of stress through the family system to adolescent [mental and behavioral health problems] is investigated as a function of (a) objective dangers of parental deployment, (b) the [mental health] of the civilian parent, and (c) civilian parent and adolescent interactions] Observational coding methodologies are integrated with parent and adolescent self- reports to gain multiple perspectives [on how youth] adapt to stress associated with parental deployment. [Two groups] of adolescents (aged 14-18) and their civilian parents will be recruited from [communities surrounding] military installations. [One group will have a parent currently deployed, whereas the sex and age- matched comparison group will be military families not currently experiencing deployment. Both groups will be interviewed about the other parent's military service history, complete questionnaires assessing mental and behavioral health symptoms, and engage in problem-solving discussions focused on problematic family issues. Parents and adolescents in deployed families also will provide details about the deployment and will discuss family problems specific to the current deployment. Analyses will examine potential mediating and moderating roles of parent-adolescent talk in the association between deployment stress and adolescents' anxiety, depression, and risk-taking behaviors. Greater understanding of the link between stressful family transitions and adolescents' mental and behavioral health symptoms can inform preventive education programs for military families and inform broader interventions for youth and families experiencing environmental stresses.]